1. Field of the Invention
The present invention relates to a thermoelectric module used suitably for cooling a heating element and so forth in an air-conditioner, cooler, semiconductor, and so forth.
2. Description of the Related Art
Conventionally, a thermoelectric element in which Peltier effect is utilized has been used as a thermoelectric element for cooling because by passing an electric current therethrough, one end generates heat and the other end absorbs heat. In particular, the thermoelectric element has been expected to be utilized as a thermoelectric module, in a broad range of, temperature control in a laser diode, temperature adjustment in the following, and so forth. The temperature adjustment is in for example, a cooling device that is compact and has a simple structure and is chlorofluorocarbon-free, a refrigerator, a constant-temperature tank, a light-detecting element, an electronic cooling element in a semiconductor-producing apparatus or the like, and a laser diode.
For example, for using an electronic component such as a laser diode so that its temperature is adjusted, the temperature adjustment is performed by detecting the temperature near the laser diode and then feedbacking the temperature to a power source for the thermoelectric module (see, for example, Japanese Unexamined Patent Publication (Kokai) No. 2003-78088). Moreover, in a refrigerator or a constant-temperature tank, the temperature adjustment is performed by, detecting the inside temperature by using a temperature-detecting element such as a thermocouple, and then feedbacking the temperature to a power source for the thermoelectric module. Specifically, as shown in FIG. 10, an electronic component such as a laser diode serving as an object to be treated is disposed on a thermoelectric module for cooling or temperature-controlling the electronic component, and the thermoelectric module is disposed on a heat exchanger for discharging heat generated by the thermoelectric module. Then, in order to control or cool the temperature so that temperature rising of the objected to be treated is suppressed and so that the temperature becomes constant, the side of the object to be treated is cooled by passing electric current through the thermoelectric module. In this time, heat generated from the thermoelectric module is discharged by flowing a fluid such as water or air through the heat exchanger. In such a thermoelectric module, when the temperature in the side thereof for the object to be treated becomes too cool, the electric current being passed through the thermoelectric module is suppressed or electric current is inversely passed through the thermoelectric module to generate heat, and thereby the temperature adjustment has been performed.
However, in a conventional apparatus, because the temperature-detecting element measures the temperature of the object to be treated and there is a distance between the thermoelectric element and the object to be treated, a time lag has been generated until the temperature transmits from the heat-absorbing or heat-generating part to the temperature-detecting element. Furthermore, the object to be treated in a refrigerator and so forth is an air, and therefore, the time lag has been larger because an air has a slow transmission of temperature. Therefore, when the water or the air flowing through the heat exchanger attached to the thermoelectric module makes a halt, the temperature in the entirety of the module comes to rapidly rise and, occasionally, the thermoelectric element is oxidized or solder that is bonding the thermoelectric element and a support substrate comes to melt.